Polyester resins have been conventionally used for a wide variety of applications such as films, PET bottles, fibers, toners, electric parts, adhesives, and pressure-sensitive adhesives because of their high heat resistance, chemical resistance, durability, and mechanical strength.
In general, polyester resins have vulnerability to hydrolysis. Therefore, for example, Patent Documents 1 and 2 describe a study conducted to develop polyester films with high durability (resistance to moisture) by adding a hydrolysis-resistant agent to improve the hydrolysis resistance of polyester resins.
On the other hand, at present, polyester resin-based adhesives do not simultaneously have high durability and good adhesive properties, although improvements have been made for good adhesive properties (adhesive strength) or high durability.